Exercise step



FIG. 1 is a perspective view of an exercise step showing my new design.

FIG. 2 is top plan view thereof

FIG. 3 is a front elevational view thereof. A rear elevations view thereof is identical.

FIG. 4 is a right side elevational view thereof. A left side elevational view thereof is identical; and,

FIG. 5 is a bottom plan view thereof.

The broken lines represent portions of the exercise step which form no part of the claimed design. 

CLAIM The ornamental design for an exercise step, as shown and described. 